What Playoffs had an Open Cup of 3rd round?
CREATE TABLE "year_by_year" (
  "year" real,
  "division" real,
  "league" text,
  "reg_season" text,
  "playoffs" text,
  "open_cup" text,
  "avg_attendance" real
);
SELECT "playoffs" FROM "year_by_year" WHERE "open_cup"='3rd round';