Sen. Bernie Sanders Bernie SandersKenosha will be a good bellwether in 2020 Biden's fiscal program: What is the likely market impact? McConnell accuses Democrats of sowing division by 'downplaying progress' on election security MORE (I-Vt.) leads for the first time in a new Hill/HarrisX poll of the Democratic presidential race, just days before the next nominating contest in Nevada.

Sanders draws 22 percent support in the survey, followed by former Vice President Joe Biden Joe BidenSenate Republicans face tough decision on replacing Ginsburg What Senate Republicans have said about election-year Supreme Court vacancies Biden says Ginsburg successor should be picked by candidate who wins on Nov. 3 MORE at 19 percent and former New York City Mayor Michael Bloomberg Michael BloombergTop Democratic super PAC launches Florida ad blitz after Bloomberg donation The Hill's 12:30 Report - Presented by Facebook - Latest with the COVID-19 relief bill negotiations The Memo: 2020 is all about winning Florida MORE at 18 percent.

Sanders and Bloomberg have both risen 2 points in the poll since earlier this month, while Biden has ticked down 4 points. All three candidates are within the poll's margin of error.

Sen. Elizabeth Warren Elizabeth WarrenBiden's fiscal program: What is the likely market impact? Warren, Schumer introduce plan for next president to cancel ,000 in student debt The Hill's 12:30 Report - Presented by Facebook - Don't expect a government check anytime soon MORE (D-Mass.) and former South Bend, Ind., Mayor Pete Buttigieg Pete ButtigiegBipartisan praise pours in after Ginsburg's death Bogeymen of the far left deserve a place in any Biden administration Overnight Defense: Woodward book causes new firestorm | Book says Trump lashed out at generals, told Woodward about secret weapons system | US withdrawing thousands of troops from Iraq MORE (D) both ticked up in the poll and are now drawing double-digit support.

Warren, who gained 3 points compared to a poll earlier this month, stands at 12 percent support, while Buttigieg gained 1 point and is at 10 percent.

Sen. Amy Klobuchar Amy KlobucharThe Hill's Morning Report - Sponsored by The Air Line Pilots Association - White House moves closer to Pelosi on virus relief bill EPA delivers win for ethanol industry angered by waivers to refiners It's time for newspapers to stop endorsing presidential candidates MORE (D-Minn.) and billionaire Tom Steyer Tom SteyerTV ads favored Biden 2-1 in past month Inslee calls Biden climate plan 'perfect for the moment' OVERNIGHT ENERGY: Trump administration finalizes plan to open up Alaska wildlife refuge to drilling | California finalizes fuel efficiency deal with five automakers, undercutting Trump | Democrats use vulnerable GOP senators to get rare win on environment MORE follow the pack at 5 percent and 3 percent, respectively. Rep. Tulsi Gabbard Tulsi GabbardRepublicans call on DOJ to investigate Netflix over 'Cuties' film Hispanic Caucus campaign arm endorses slate of non-Hispanic candidates Gabbard says she 'was not invited to participate in any way' in Democratic convention MORE (D-Hawaii) did not register support in the poll.

The survey indicates that the Democratic White House race remains fluid, with 8 percent of Democratic and Democratic-leaning independent voters saying they are unsure who they support.

"Nationally, the Democratic contest is increasingly starting to look like a three way race between Sanders, Biden and Bloomberg. Bloomberg has been growing steadily and is within striking range of both other candidates among Democrats and Democratic leaning independents," Dritan Nesho, Founder and CEO of HarrisX, told The Hill.

"Bloomberg’s first debate performance, and Biden’s overall showing, in the Nevada primary will determine the future dynamic of the race," he added.

Six top Democratic contenders are set to face off in the party's 9th presidential debate on Wednesday night in Nevada as the candidates compete ahead of the state's caucuses on Saturday.

Sanders is entering the debate as a clear frontrunner in polls, while the Las Vegas debate will also feature Bloomberg on stage with other candidates for the first time.

"Sanders has positioned himself as the leader in the Democratic sweepstakes by attracting 54% of the potential Democratic electorate under 45 years of age, and 46% who consider themselves as progressives," Lee Miringoff, director of the Marist Poll, told The Hill.

"No other Democratic candidate breaks 20% with younger voters or progressives. He is also running up the score among male voters in the potential D Democratic electorate with 41%. Again, no other Democratic candidate breaks 20% with this group. And, Sanders has gotten within the margin of error among African American voters against Biden by gaining 28% of these voters to 31% for Biden."

"For these, reasons, Sanders is the front-runner going into the debate," he added.

The Hill-HarrisX poll was conducted online among 449 registered Democratic and Democratic-leaning independent voters between Feb. 14 and 15. It has a margin of error of plus or minus 4.6 percentage points.

—Gabriela Schulte