What county has $51,456 income per capita?
CREATE TABLE "counties" (
  "county" text,
  "per_capita_income" text,
  "median_household_income" text,
  "median_family_income" text,
  "population" real,
  "number_of_households" real
);
SELECT "county" FROM "counties" WHERE "per_capita_income"='$51,456';