Pennsylvania State Rep. Fred Keller won the Pennsylvania House 12th district special election, according to the New York Times.

Keller defeated Democrat and professor at Penn State University Marc Friedenberg in a special election Tuesday. The congressional seat became vacant after former Rep. Tom Marino (R-PA), who easily beat Friedenberg in the 2018 midterm elections, resigned less than one month into this term.

The Pennsylvania Republican’s victory serves President Donald Trump as well. Trump held a rally in Pennsylvania on Monday.

Ahead of the election, Trump said he endorsed Keller and contended that the election would serve as a referendum on his presidential administration.

“Go get em, Fred,” Trump told Keller on Monday. “It’s a little bit of a referendum.” President Trump then said that if Keller wins the special election, the media will not widely report the story; however, if Keller loses the election, Trump said that they will play it up as one of the biggest political events in recent memory.

“Go get ‘em, Fred," Trump tells GOP congressional candidate Fred Keller. "It's a little bit of a referendum," says pres of the special election. If Keller wins, @POTUS says press won't report it, but if he loses, they'll portray as the biggest political event ever. pic.twitter.com/V4v0B43NLR — Mark Knoller (@markknoller) May 20, 2019

Keller’s victory could also serve as a referendum on Trump’s vs former Vice President Joe Biden’s popularity in Pennsylvania.

During the rally on Monday, Trump reminded Pennsylvanians that Biden abandoned them to become a senator in Delaware.

“Don’t forget, Biden deserted you, he’s not from Pennsylvania, I guess he was born here, but he left you, folks, he left you for another state,” Trump said.

“He left you for another state, and he didn’t take care of you because he didn’t take care of your jobs,” Trump added. “He let other countries come in and rip off America.”