Which Nationality has a 2.24 of xo, and a 2.20 of xo?
CREATE TABLE "final" (
  "athlete" text,
  "nationality" text,
  "2_15" text,
  "2_20" text,
  "2_24" text,
  "2_27" text,
  "result" real
);
SELECT "nationality" FROM "final" WHERE "2_24"='xo' AND "2_20"='xo';