What is the highest season for a bowl game of the 1993 Independence Bowl?
CREATE TABLE "summary_table" (
  "num" real,
  "season" real,
  "bowl_game" text,
  "result" text,
  "opponent" text,
  "stadium" text,
  "location" text,
  "attendance" text
);
SELECT MAX("season") FROM "summary_table" WHERE "bowl_game"='1993 Independence Bowl';