CREATE TABLE "round_6" (
  "home_team" text,
  "home_team_score" text,
  "away_team" text,
  "away_team_score" text,
  "venue" text,
  "crowd" real,
  "date" text
);

Question: Which date did richmond play as away?
SQL: SELECT "date" FROM "round_6" WHERE "away_team"='richmond';