What conference did the city of Valparaiso join?
CREATE TABLE "former_members" (
  "school" text,
  "city" text,
  "mascot" text,
  "county" text,
  "year_joined" real,
  "previous_conference" text,
  "year_left" real,
  "conference_joined" text
);
SELECT "conference_joined" FROM "former_members" WHERE "city"='valparaiso';