CREATE TABLE table_24994 ("Year" TEXT, "Date" TEXT, "Driver" TEXT, "Team" TEXT, "Manufacturer" TEXT, "Laps" TEXT, "Miles  ( km ) " TEXT, "Race Time" TEXT, "Average Speed  ( mph ) " TEXT, "Report" TEXT)

Who made the car that won the race on May 21?
SELECT "Manufacturer" FROM table_24994 WHERE "Date" = 'May 21'
SELECT "Manufacturer" FROM "table_24994" WHERE "Date" = 'May 21'