CREATE TABLE table_203_408 (id DECIMAL, "rd." DECIMAL, "grand prix" TEXT, "date" TEXT, "location" TEXT, "pole position" TEXT, "fastest lap" TEXT, "winning driver" TEXT, "constructor" TEXT, "report" TEXT)

how many times has nigel mansell been the winning driver ?
SELECT COUNT(*) FROM table_203_408 WHERE "winning driver" = 'nigel mansell'
SELECT COUNT(*) FROM "table_203_408" WHERE "winning driver" = 'nigel mansell'