user: Question: Name the number of districts for December 1799
Columns: ['Con- gress', 'District', 'Vacator', 'Election date', 'Successor', 'Took seat']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['2nd', 'New York 1st', 'James Townsend ( F ) (died)', 'April 26 to 28, 1791', 'Thomas Tredwell ( D-R )', 'October 24, 1791']
SQL:

assistant: SELECT COUNT("District") FROM "Table" WHERE "Election date" = 'December 1799';