CREATE TABLE table_56817 ("Entrant" TEXT, "Constructor" TEXT, "Chassis" TEXT, "Engine \\u2020" TEXT, "Tyre" TEXT, "Driver" TEXT, "Rounds" TEXT)

Who was the constructor for a FW20 chassis?
SELECT "Constructor" FROM table_56817 WHERE "Chassis" = 'fw20'
SELECT "Constructor" FROM "table_56817" WHERE "Chassis" = 'fw20'