What is the number of networks when the size of rest bit field is 8?
CREATE TABLE "introduction_of_address_classes" (
  "class" text,
  "leading_bits" real,
  "size_of_network_number_bit_field" text,
  "size_of_rest_bit_field" text,
  "number_of_networks" text,
  "addresses_per_network" text,
  "start_address" text,
  "end_address" text
);
SELECT "number_of_networks" FROM "introduction_of_address_classes" WHERE "size_of_rest_bit_field"='8';