CREATE TABLE table_70015 ("Year" FLOAT, "Entrant" TEXT, "Chassis" TEXT, "Engine" TEXT, "Points" FLOAT)

Which Entrant has a vanwall straight-4 engine?
SELECT "Entrant" FROM table_70015 WHERE "Engine" = 'vanwall straight-4'
SELECT "Entrant" FROM "table_70015" WHERE "Engine" = 'vanwall straight-4'