CREATE TABLE table_204_511 (id NUMBER, "number" NUMBER, "driver" CLOB, "entrant" CLOB, "chassis" CLOB, "engine" CLOB, "tyre" CLOB)

how many racers had an offenhauser engine ?
SELECT COUNT("driver") FROM table_204_511 WHERE "engine" = 'offenhauser'
SELECT COUNT("driver") FROM "table_204_511" WHERE "engine" = 'offenhauser'