What is the latest task number for which Cathy is head of household?
CREATE TABLE "head_of_household_and_hand_grenade" (
  "task_no" real,
  "date_given" text,
  "head_of_household" text,
  "hand_grenade_user" text,
  "hand_grenade_recipient" text
);
SELECT MAX("task_no") FROM "head_of_household_and_hand_grenade" WHERE "head_of_household"='cathy';