Which Year has a Venue of bydgoszcz, poland, and an Event of junior team?
CREATE TABLE "achievements" (
  "year" real,
  "competition" text,
  "venue" text,
  "position" text,
  "event" text
);
SELECT AVG("year") FROM "achievements" WHERE "venue"='bydgoszcz, poland' AND "event"='junior team';