What is the lowest week that has 7:15 p.m. as the time (cst) and fedexfield as the game site?
CREATE TABLE "schedule" (
  "week" real,
  "date" text,
  "time_cst" text,
  "opponent" text,
  "result" text,
  "game_site" text,
  "record" text,
  "nfl_recap" text
);
SELECT MIN("week") FROM "schedule" WHERE "time_cst"='7:15 p.m.' AND "game_site"='fedexfield';