Which Points against has a Lost of 13, and Points for of 671?
CREATE TABLE "2004_05_table" (
  "club" text,
  "played" text,
  "drawn" text,
  "lost" text,
  "points_for" text,
  "points_against" text,
  "points_difference" text,
  "points" text
);
SELECT "points_against" FROM "2004_05_table" WHERE "lost"='13' AND "points_for"='671';