What is the percentage of registered voters in which the d-r spread is +10.4%?
CREATE TABLE "table1_27003223_4" (
  "city" text,
  "population" real,
  "registered_voters" text,
  "democratic" text,
  "republican" text,
  "d_r_spread" text,
  "other" text,
  "no_party_preference" text
);
SELECT "registered_voters" FROM "table1_27003223_4" WHERE "d_r_spread"='+10.4%';