What year did the Ingots, who left after 2007, join?
CREATE TABLE "membership" (
  "school" text,
  "location" text,
  "mascot" text,
  "county" text,
  "year_joined" real,
  "previous_conference" text,
  "year_left" real,
  "conference_joined" text
);
SELECT COUNT("year_joined") FROM "membership" WHERE "mascot"='ingots' AND "year_left">2007;