Table: khajuraho_loksabha_electorates_2003
Columns: constituency_number
name
reserved_for_sc_st_none
district
number_of_electorates_2003

Question: What is the average number of electorates (2003) reserved for sc with a constituency number of 50?
SQL: SELECT AVG("number_of_electorates_2003") FROM khajuraho_loksabha_electorates_2003 WHERE "reserved_for_sc_st_none" = 'sc' AND "constituency_number" = '50'