What is the year of entry for the University of Essex?
CREATE TABLE "british_universities_and_colleges_sport" (
  "team" text,
  "university" text,
  "location" text,
  "year_entered_league" real,
  "2013_14_division" text
);
SELECT "year_entered_league" FROM "british_universities_and_colleges_sport" WHERE "university"='university of essex';