What is the Constituency Number when the Number of Electorates (2003) is more than 156,910, and Reserved for sc?
CREATE TABLE "assembly_segments" (
  "constituency_number" text,
  "name" text,
  "reserved_for_sc_st_none" text,
  "district" text,
  "number_of_electorates_2003" real
);
SELECT "constituency_number" FROM "assembly_segments" WHERE "number_of_electorates_2003">'156,910' AND "reserved_for_sc_st_none"='sc';