user: Question: What is the average number of electorates (2003) reserved for SC with a constituency number of 50?
Columns: ['Constituency number', 'Name', 'Reserved for ( SC / ST /None)', 'District', 'Number of electorates (2003)']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['43', 'Niwari', 'None', 'Tikamgarh', 222145.0]
SQL:

assistant: SELECT AVG("Number of electorates (2003)") FROM "Table" WHERE "Reserved for ( SC / ST /None)" = 'SC' AND "Constituency number" = '50';