What is the rank of the episode with a share of 6 and timeslot rank smaller than 4?
CREATE TABLE "weekly_ratings" (
  "episode" text,
  "air_date" text,
  "rating" real,
  "share" real,
  "rating_share_18_49" text,
  "viewers_m" real,
  "timeslot_rank" real,
  "night_rank" text,
  "overall_rank" real
);
SELECT AVG("overall_rank") FROM "weekly_ratings" WHERE "share"=6 AND "timeslot_rank"<4;