what's the earliest year that the wimbledon opponent was zheng jie?
CREATE TABLE "women" (
  "aces" real,
  "player" text,
  "opponent" text,
  "year" real,
  "event" text,
  "sets" real,
  "result" text
);
SELECT MIN("year") FROM "women" WHERE "event"='wimbledon' AND "opponent"='zheng jie';