CREATE TABLE table_27136 ("Round" TEXT, "Circuit" TEXT, "Date" TEXT, "Class A Winner" TEXT, "Class B Winner" TEXT, "Class C Winner" TEXT, "Class D Winner" TEXT)

Who was the Class D winner in round 6?
SELECT "Class D Winner" FROM table_27136 WHERE "Round" = '6'
SELECT "Class D Winner" FROM "table_27136" WHERE "Round" = '6'