Openly gay Mark Pocan on Tuesday won the Democratic primary for Wisconsin's 2nd Congressional District, formerly represented by Rep. Tammy Baldwin.

Pocan soundly defeated three rivals, including fellow state Rep. Kelda Helen Roys, his main opponent. He will go on to face Republican Chad Lee in the fall.

Pocan, who turned 48 on Tuesday, was greeted with birthday wishes as he approached the podium last night for his victory speech.

He thanked his supporters and told them he understood that he has “big shoes to fill” representing the district.

“This is the seat of Fighting Bob La Follette. This is the seat of Bob Kastenmeier. And this is the seat of Tammy Baldwin,” he said.

The district, which includes Madison, runs heavily Democratic and Pocan is considered a shoe-in to replace Baldwin, who is vying for a seat in the U.S. Senate.

(Related: Tammy Baldwin endorsed by lesbian super PAC.)

Pocan has the endorsement of the Gay & Lesbian Victory Fund, a group dedicated to supporting openly gay candidates for elected office.

“Mark Pocan is an outstanding public servant who will be a strong and authentic voice for LGBT Americans in Congress,” Chuck Wolfe, CEO of the Victory Fund, told gay weekly the Washington Blade. “It's fitting that as Congresswoman Tammy Baldwin fights to win a historic victory in the Senate, Mark Pocan will follow in her footsteps as one of the most powerful voices for LGBT equality in America.”