Former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE is leading the 2020 Democratic presidential field, according to a new poll that also shows support for Sen. Bernie Sanders (I-Vt.) growing.

Just less than one-third of Democratic primary voters surveyed — 31 percent — said they support Biden, according to the Emerson poll released Tuesday, relatively unchanged from July.

But Sanders saw a 4-point uptick since last month, rising to 24 percent in the new survey.

It's the second Emerson poll in a row in which Sanders saw an increase in support. ADVERTISEMENT

Support for Biden and Sanders differs greatly by voter age, pollsters found. Sanders received support from 36 percent of respondents under the age of 50 and just 11 percent of those 50 and older.

Biden, by comparison, has the support of 21 percent of respondents under 50 and 44 percent of those 50 and over.

Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) was the third-most popular candidate among Democrats in the new poll, at 15 percent. Sen. Kamala Harris Kamala HarrisTexas Democratic official urges Biden to visit state: 'I thought he had his own plane' The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements A game theorist's advice to President Trump on filling the Supreme Court seat MORE (D-Calif.) trails Warren at 10 percent.

Tech entrepreneur Andrew Yang Andrew YangBiden's latest small business outreach is just ... awful Doctor who allegedly assaulted Evelyn Yang arrested on federal charges The Hill's Campaign Report: Biden weighs in on police shootings | Who's moderating the debates | Trump trails in post-convention polls MORE's support was up 2 points from July to 4 percent, and South Bend, Ind., Mayor Pete Buttigieg Pete ButtigiegBillionaire who donated to Trump in 2016 donates to Biden The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Buttigieg stands in as Pence for Harris's debate practice MORE stood at 3 percent, down 3 points.

Pollsters also found that Sanders and Biden were the only two candidates to beat President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE in head-to-head match-ups. Trump trailed Biden by 8 percent, at 46 percent to 54 percent. The president trailed Sanders by 4 points, 48 percent to 52 percent.

Warren and Harris were tied with Trump at 50 percent each in hypothetical match-ups and Buttigieg trailed the president by 2 points, 49 percent to 51 percent.

The poll surveyed 1,458 registered voters between Aug. 24 and 26. The data was collected using an interactive voice response system solely on landlines and an online panel provided by Amazon Turk, a crowd sourcing website for businesses.

There is a margin of error of 2.5 percentage points.