CREATE TABLE table_51984 ("Race Name" TEXT, "Circuit" TEXT, "Date" TEXT, "Winning driver" TEXT, "Constructor" TEXT, "Report" TEXT)

Which Constructor has the Winning Driver, Jim Clark and the Circuit, Syracuse?
SELECT "Constructor" FROM table_51984 WHERE "Winning driver" = 'jim clark' AND "Circuit" = 'syracuse'
SELECT "Constructor" FROM "table_51984" WHERE "Circuit" = 'syracuse' AND "Winning driver" = 'jim clark'