When καθ are the letters what is the nickname?
CREATE TABLE "national_panhellenic_conference_npc" (
  "letters" text,
  "organization" text,
  "nickname" text,
  "founding_date" text,
  "founding_university" text,
  "type" text,
  "canadian_chapters" text
);
SELECT "nickname" FROM "national_panhellenic_conference_npc" WHERE "letters"='ΚΑΘ';