Which rebound was 8 and has and ast that was less than 57?
CREATE TABLE "players" (
  "nationality" text,
  "no_a" text,
  "pos_a" text,
  "from" text,
  "school_club" text,
  "pts_b" real,
  "reb_b" real,
  "ast_b" real
);
SELECT AVG("reb_b") FROM "players" WHERE "no_a"='8' AND "ast_b"<57;