What 1957 engine has a Chassis of connaught type b?
CREATE TABLE "complete_world_championship_formula_one_" (
  "year" real,
  "entrant" text,
  "chassis" text,
  "engine" text,
  "points" real
);
SELECT "engine" FROM "complete_world_championship_formula_one_" WHERE "chassis"='connaught type b' AND "year">1957;