CREATE TABLE table_74919 ("Race" CLOB, "Class ( es ) " CLOB, "Length/Duration" CLOB, "Circuit" CLOB, "Date" CLOB)

What was the circuit had a race on September 20.
SELECT "Circuit" FROM table_74919 WHERE "Date" = 'september 20'
SELECT "Circuit" FROM "table_74919" WHERE "Date" = 'september 20'