A University of North Florida poll released Thursday of likely Democratic primary voters shows incumbent District 5 Congressman Al Lawson with a commanding lead.

The poll shows 48 percent said they would vote for Lawson, while 29 percent said they would vote for former Jacksonville Mayor Alvin Brown.

More: UNF Bown/Lawson Poll, Full Results

“Brown supporters might point to the large number of undecided voters as potential supporters, but late deciders never swing entirely for one candidate,” said Dr. Michael Binder, UNF Public Opinion Research Lab faculty director and associate professor of political science, about Lawson’s 19 point lead.

Related: Election News & Voter Guide

“Roughly half of Congressional District 5 voters are in Duval County, and even though Brown is ahead by 18 percentage points in Duval, that isn’t nearly enough. Lawson is ahead by nearly 60 percentage points in the counties west of Duval,” said Binder.

The poll has a margin of error of plus or minus 4.9 percent, according to UNF.

Brown, who appeared on WJCT's First Coast Connect Monday, said he was confident of an upset victory.

Related: Listen To The Brown Interview On First Coast Connect

“We’ve got to invest in our local public schools, got to invest in teachers. Al Lawson is the only Democrat who voted with Jeb Bush in the Florida Senate for vouchers to drain billions of dollars from public education,” said Brown.

The poll also held some good news for Tallahassee Mayor Andrew Gillum, who’s in a crowded Democratic primary for Florida governor. Previous polls had Gillum trailing far behind former North Florida Congresswoman Gwen Graham, as well as former Miami Beach Mayor Philip Levine.

UNF found Gillum has plurality support among both Lawson and Brown voters in District 5, which stretches from Jacksonville westward to just past Tallahassee.

Binder said, “High turnout in this area could propel Gillum to victory on August 28.”

Bill Bortzfield can be reached at bbortzfield@wjct.org, 904-358-6349 or on Twitter at @BortzInJax.