For the team with a class of gt2 and 3:59.820 on day 2, what was the behind?
CREATE TABLE "qualifying_times" (
  "team" text,
  "class" text,
  "day_1" text,
  "day_2" text,
  "behind" text
);
SELECT "behind" FROM "qualifying_times" WHERE "class"='gt2' AND "day_2"='3:59.820';