Which year did the school with enrollment of 413 join?
CREATE TABLE "membership" (
  "school_ihsaa_i_dnum" text,
  "location" text,
  "mascot" text,
  "enrollment" real,
  "ihsaa_class" text,
  "num_county" text,
  "year_joined" real
);
SELECT "year_joined" FROM "membership" WHERE "enrollment"=413;