When Platense was the away team on 16 August 2008 how many people attended the game?
CREATE TABLE "round_6" (
  "date" text,
  "home" text,
  "score" text,
  "away" text,
  "attendance" real
);
SELECT "attendance" FROM "round_6" WHERE "date"='16 august 2008' AND "away"='platense';