Which Opponent in the final has a Score of 6–3, 3–6, 6–8?
CREATE TABLE "runners_up_17" (
  "date" real,
  "tournament" text,
  "surface" text,
  "partnering" text,
  "opponent_in_the_final" text,
  "score" text
);
SELECT "opponent_in_the_final" FROM "runners_up_17" WHERE "score"='6–3, 3–6, 6–8';