In 2008, what was the world ranking that ranked 5th in L.A.?
CREATE TABLE "table" (
  "index_year" text,
  "author_editor_source" text,
  "year_of_publication" text,
  "countries_sampled" real,
  "world_ranking_1" text,
  "ranking_l_a_2" text
);
SELECT "world_ranking_1" FROM "table" WHERE "ranking_l_a_2"='5th' AND "year_of_publication"='2008';