CREATE TABLE table_204_659 (id DECIMAL, "seat" TEXT, "state" TEXT, "majority" DECIMAL, "member" TEXT, "party" TEXT)

what party had the most seats ?
SELECT "party" FROM table_204_659 GROUP BY "party" ORDER BY COUNT("seat") DESC LIMIT 1
SELECT "party" FROM "table_204_659" GROUP BY "party" ORDER BY COUNT("seat") DESC NULLS LAST LIMIT 1