Which constructor had a Time/Retired of collision, where the grid number was less than 18 and Nick Heidfeld was the driver?
CREATE TABLE "race" (
  "driver" text,
  "constructor" text,
  "laps" real,
  "time_retired" text,
  "grid" real
);
SELECT "constructor" FROM "race" WHERE "time_retired"='collision' AND "grid"<18 AND "driver"='nick heidfeld';