What building is in ljubljana, proposed in 2010, and has 15 floors?
CREATE TABLE "tallest_proposed" (
  "rank" real,
  "name" text,
  "location" text,
  "height_feet_metres" text,
  "floors" text,
  "year_proposed" text
);
SELECT "name" FROM "tallest_proposed" WHERE "location"='ljubljana' AND "year_proposed"='2010' AND "floors"='15';