What is the date of the German Grand Prix?
CREATE TABLE "grands_prix" (
  "round" real,
  "date" text,
  "grand_prix" text,
  "circuit" text,
  "125cc_winner" text,
  "250cc_winner" text,
  "moto_gp_winner" text,
  "report" text
);
SELECT "date" FROM "grands_prix" WHERE "grand_prix"='German Grand Prix';