What is the highest episode number in which Jamie Oliver guest-hosted?
CREATE TABLE "series_2" (
  "episode_number" real,
  "air_date" text,
  "guest_host" text,
  "musical_guest_song_performed" text,
  "who_knows_the_most_about_the_guest_host_panelists" text
);
SELECT MAX("episode_number") FROM "series_2" WHERE "guest_host"='jamie oliver';