Table: us_house_special_elections
Columns: con_gress
district
vacator
election_date
successor
took_seat

Question: Name the number of districts for december 1799
SQL: SELECT COUNT("district") FROM us_house_special_elections WHERE "election_date" = 'December 1799'

Question: Name the vacator for took seat being january 29, 1813
SQL: SELECT "vacator" FROM us_house_special_elections WHERE "took_seat" = 'January 29, 1813'