With a 1st run of 53.300 (7), and greater than 21 total, what is the average rank?
CREATE TABLE "heat_1" (
  "rank" real,
  "name" text,
  "1st_run" text,
  "2nd_run" text,
  "3rd_run" text,
  "total" real
);
SELECT AVG("rank") FROM "heat_1" WHERE "1st_run"='53.300 (7)' AND "total">21;