On March 12, 1815, a few days after the legal start of the 14th Congress, but long before the first meeting of that Congress, David Bard (DR), who'd been re-elected to the 9th district, died. A special election was held on October 10 to fill the vacancy left by his death.
Election results
The 9th district did not change parties with this election. On December 11, Burnside took his seat in the 14th Congress. He would subsequently resign, in April, 1816, to accept a judicial position, resulting in a second special election. He thus served for only a few months as Representative.
References
Pennsylvania's 9th congressional district special election, 1815 Wikipedia(Text) CC BY-SA