What is the USN 2013 ranking with a BW 2013 ranking less than 1000, a Forbes 2011 ranking larger than 17, and a CNN 2011 ranking less than 13?
CREATE TABLE "current_individual_rankings" (
  "location_state_city" text,
  "usn_2013" real,
  "bw_2013" real,
  "forbes_2011" real,
  "ec_2013" real,
  "ft_2011" real,
  "ae_2011" real,
  "cnn_2011" real,
  "bi_2013" real,
  "arwu_2012" real
);
SELECT SUM("usn_2013") FROM "current_individual_rankings" WHERE "bw_2013"<1000 AND "forbes_2011">17 AND "cnn_2011"<13;