What is the BW 2013 ranking of Washington, D.C., which has an ARWU 2012 ranking greater than 51?
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 "bw_2013" FROM "current_individual_rankings" WHERE "arwu_2012">51 AND "location_state_city"='washington, d.c.';