What is the lowest 06-10 totals with a pubs 2010 of 68 and a 07-11 totals larger than 305?
CREATE TABLE "world_ranking_of_chemical_engineering_sc" (
  "school" text,
  "location" text,
  "pubs_2010" real,
  "totals_06_10" real,
  "rank_06_10" real,
  "pubs_2011" real,
  "totals_07_11" real,
  "rank_07_11" real,
  "world_ranking" text
);
SELECT MIN("totals_06_10") FROM "world_ranking_of_chemical_engineering_sc" WHERE "pubs_2010"=68 AND "totals_07_11">305;