What are the number of days did the ulster unionist Party have the constituate fermanagh and south tyrone?
CREATE TABLE "since_1945" (
  "candidate" text,
  "party" text,
  "constituency" text,
  "year" text,
  "days" text
);
SELECT "days" FROM "since_1945" WHERE "party"='ulster unionist' AND "constituency"='fermanagh and south tyrone';