What are the lowest points for the engines of the Lamborghini v12 and the Chassis on Minardi m191b?
CREATE TABLE "complete_formula_one_results" (
  "year" real,
  "entrant" text,
  "chassis" text,
  "engine" text,
  "points" real
);
SELECT MIN("points") FROM "complete_formula_one_results" WHERE "engine"='lamborghini v12' AND "chassis"='minardi m191b';