CREATE TABLE table_1275 ("Con- gress" TEXT, "District" TEXT, "Vacator" TEXT, "Election date" TEXT, "Successor" TEXT, "Took seat" TEXT)

Name the number of districts for december 1799
SELECT COUNT("District") FROM table_1275 WHERE "Election date" = 'December 1799'
SELECT COUNT("District") FROM "table_1275" WHERE "Election date" = 'December 1799'