Baca said he was making the trip Wednesday at the request of Democratic minority leader Dick Gephardt.
"I'm going to cast a vote for a balanced budget," he told a cheering crowd at his victory celebration Tuesday night.
California Secretary of State Bill Jones certified the victory shortly after midnight, making Baca eligible to be sworn in on the floor of the House almost immediately.
With all 202 precincts reporting, Baca had 22,766 votes, or 51.7 percent, and Republican Elia Pirozzi had 19,194 votes, or 43.6 percent. The remaining votes were split between two minor party candidates.
Baca's victory means that Democrats will continue their nearly two-decade control over a district at the inland edge of Los Angeles' sprawl.
The runoff followed a bruising special election in September in which Baca challenged Brown's widow, Marta Macias Brown. While congressional widows have found success elsewhere, Baca refused to back down, causing some division in the state Democratic Party that still lingers.
Although Brown called for unity afterward, she never openly endorsed Baca.
The two-month campaign was characterized more by charges of ethical missteps than debate over national issues.
"We won clean," Baca told supporters, criticizing what he described as a negative campaign by his opponent.
In recent weeks, Republicans hoping to build on their narrow majority in the House filed two complaints against Baca, alleging he violated federal election laws by failing to file a financial disclosure statement and then again for using a taxpayer-financed brochure to promote his candidacy.
Although he admitted to a staff error with the brochures, Baca said the charges were a desperate attempt by Pirozzi, who badly lagged in the polls, to get ahead.
"We were hit with a shotgun. They just kept firing at us," Baca told supporters. "It didn't work because it was negative campaigning. People are tired of negative campaigning."
Pirozzi blamed himself for the defeat.
"If there was someone who fell short in this campaign, it was me," he said. "I wish things could have been different. God bless you and let's keep fighting."
Gov. Gray Davis called a special primary election Jan. 11 to fill the state Senate seat left by Baca, who resigned Tuesday.
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