user: Question: What is the sum of the serial numbers for Narowal City?
Columns: ['Serial No.', 'District', 'Headquartered City', 'City Population (2009)', 'City Area(km 2 )']
Types: ['real', 'text', 'text', 'real', 'real']
Sample row: [1.0, 'Attock District', 'Attock City', 94620.0, 20.0]
SQL:

assistant: SELECT SUM("Serial No.") FROM "Table" WHERE "Headquartered City" = 'Narowal City';