How many people participated in the Rasmussen Reports poll on October 13, 2010?
CREATE TABLE "general_election" (
  "poll_source" text,
  "date_s_administered" text,
  "sample_size" text,
  "margin_of_error" text,
  "jerry_brown_d" text,
  "meg_whitman_r" text
);
SELECT "sample_size" FROM "general_election" WHERE "poll_source"='rasmussen reports' AND "date_s_administered"='october 13, 2010';