Colbert Busch, a businesswoman and the sister of comedian Stephen Colbert, defeated token opposition on Tuesday to win the nomination. The Associated Press has called the race.

She faces an uphill race in the GOP-leaning district, though former South Carolina Gov. Mark Sanford's (R) personal troubles give Democrats an opening to pick up the seat, and House special elections are notoriously hard to predict. Sanford advanced to a runoff in the GOP primary, though his second-round opponent has not yet been decided.

Both parties were quick to comment, though it is still an open question as to who her opponent will be.

"Congratulations to Elizabeth Colbert Busch on her victory. Elizabeth is an accomplished professional in education and business who has a record of problem solving and bringing diverse groups together to create jobs," Democratic Congressional Campaign Committee Chairman Steve Israel (D-N.Y.) said in a statement after she won. "The people of South Carolina are tired of this Congress's extreme ideology and dysfunction. Elizabeth Colbert Busch offers a breath of fresh air, standing on the side of sensible solutions that strengthen the middle class."

The GOP fired back.

"Elizabeth Colbert Busch and her liberal-Obama policies are dramatically out-of-step with South Carolina values," National Republican Congressional Committee spokeswoman Katie Prill said in a statement. "Her support for pushing the will of unions over South Carolina jobs proves she will be a rubber stamp for President Obama's job-destroying agenda. Republicans can rest assured that our nominee will champion pro-growth policies that will bring jobs back to South Carolina."

—This report was updated at 9:55 p.m.