On June 29, 1837, a special election was held in Pennsylvania's 3rd congressional district to fill a vacancy left by the death of Francis J. Harper (D) on March 18, 1837.
Election results
Naylor had been narrowly defeated in the 1836 election for the 3rd district. He took his seat on September 4, 1837, at the start of the 1st session of the 25th Congress
References
Pennsylvania's 3rd congressional district special election, 1837 Wikipedia(Text) CC BY-SA