What was the maximum finish position of the car whose constructor was Joe Gibbs Racing, driven by Denny Hamlin?
CREATE TABLE "race_results" (
  "pos" real,
  "grid" real,
  "car" real,
  "driver" text,
  "constructor" text,
  "manufacturer" text,
  "laps" real,
  "laps_led" real,
  "points" real
);
SELECT MAX("pos") FROM "race_results" WHERE "constructor"='Joe Gibbs Racing' AND "driver"='Denny Hamlin';