When has a Site of tainan city and a Score of 8–6?
CREATE TABLE "chinese_professional_baseball_league" (
  "year" real,
  "winning_team" text,
  "losing_team" text,
  "score" text,
  "site" text
);
SELECT "year" FROM "chinese_professional_baseball_league" WHERE "site"='tainan city' AND "score"='8–6';