CREATE TABLE "round_3" (
  "home_team" text,
  "home_team_score" text,
  "away_team" text,
  "away_team_score" text,
  "venue" text,
  "crowd" real,
  "date" text
);

Question: What's the average crowd size when the venue is western oval?
SQL: SELECT AVG("crowd") FROM "round_3" WHERE "venue"='western oval';