CREATE TABLE table_54651 ("Race Name" TEXT, "Circuit" TEXT, "Date" TEXT, "Winning driver" TEXT, "Constructor" TEXT, "Report" TEXT)

Who is the constructor whose circuit was Oulton Park?
SELECT "Constructor" FROM table_54651 WHERE "Circuit" = 'oulton park'
SELECT "Constructor" FROM "table_54651" WHERE "Circuit" = 'oulton park'