What type of engine does a 1951 alfa romeo 159m chasis have?
CREATE TABLE "complete_formula_one_world_championship_" (
  "year" real,
  "entrant" text,
  "chassis" text,
  "engine" text,
  "points" real
);
SELECT "engine" FROM "complete_formula_one_world_championship_" WHERE "year"=1951 AND "chassis"='alfa romeo 159m';