CREATE TABLE table_68065 ("Name" TEXT, "Circuit" TEXT, "Date" TEXT, "Winning driver" TEXT, "Winning constructor" TEXT, "Report" TEXT)

Which driver won when o.m. was the winning constructor ?
SELECT "Winning driver" FROM table_68065 WHERE "Winning constructor" = 'o.m.'
SELECT "Winning driver" FROM "table_68065" WHERE "Winning constructor" = 'o.m.'