(MARVIN JOSEPH/The Washington Post)

Democrats seeking to take control of Virginia’s House of Delegates have asked a federal judge to order a new election to rectify a delegate’s race tainted by mix-ups over district lines.

Republican Robert Thomas beat Democrat Joshua Cole by 82 votes on Nov. 7 in a contest to fill the seat being vacated by retiring Speaker William J. Howell (R-Stafford). But the outcome, which could affect which party leads the chamber, is in dispute because of errors that led 147 voters to cast ballots in the wrong race.

Democrats on Wednesday filed an amended complaint, updating a lawsuit filed Nov. 21 in U.S. District Court in Alexandria.

The original suit, filed on behalf of three voters who were denied the chance to vote in the proper race, sought a temporary restraining order to stop Virginia’s Board of Elections from certifying the results of 28th District House race. U.S. Judge T.S. Ellis III denied that request but did not dismiss the suit, allowing for Wednesday’s filing.

The elections board certified the results last week. Members said they were required by state law to certify the results despite irregularities and were powerless to require any available remedies, such as ordering a new election. They also said that certification was necessary before other challenges, such as a recount, could begin.

The amended complaint asks the judge to order the state to decertify the election and to block Thomas from being seated as a delegate when the General Assembly convenes in January. It also asks the judge to issue an order “providing for a new election to determine the representative of District 28 in the House of Delegates.”

“It is imperative that every voter is allowed to vote in the district they were properly assigned,” House Minority Leader David J. Toscano (D-Charlottesville) and Democratic Caucus Chairwoman Charniele L. Herring (D-Alexandria) said in a written statement jointly issued to announce the filing. “Having a new election where mistakes are corrected will allow voters to trust the system and be assured that their Delegate was duly elected. Democrats remain committed to ensuring the accuracy of our elections.”

Parker Slaybaugh, spokesman for Del. M. Kirkland Cox (R-Colonial Heights), who is in line to become speaker if Republicans hold the majority, said House Republicans were dismayed by the filing.

“We are disappointed that Democrats continue to pursue unnecessary litigation in federal court,” Slaybaugh said in a written statement. “As Judge Ellis has already ruled, there is a clear state process that should be followed. We will continue to follow that process in good faith.”

Cole also has filed for a recount — one of three that Democrats are pursuing in tight races they lost, including one with a margin of just 10 votes. A date for that recount has not been officially set but Democrats and Republicans say it is likely to take place Dec. 21.

Republicans are seeking a fourth recount, in the race that Del. G. Manoli Loupassi (R-Richmond) lost to Democrat Dawn Adams by 336 votes. That recount is scheduled for Dec. 20.

Before the election, Republicans enjoyed a 66-to-34 majority in the House. Now the count is 49 Democrats and 51 Republicans. Democrats, who also swept statewide offices for governor, lieutenant governor and attorney general, need one more House win to force a power-sharing deal with Republicans and two more to take control of the chamber for the first time since 2000.