What is the capacity when the 2007–08 season was 1st Serie D/I?
CREATE TABLE "girone_c" (
  "club" text,
  "city" text,
  "stadium" text,
  "capacity" real,
  "2007_08_season" text
);
SELECT "capacity" FROM "girone_c" WHERE "2007_08_season"='1st serie d/i';