user: Question: What is the registration of the station with a Retained type and a station number of C03?
Columns: ['Station Number', 'District', 'Location', 'Type', 'Appliances', 'Registrations']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['C14', 'Peterborough', 'Dogsthorpe', 'Wholetime', '1 WrL, 1 TL, 1 RV', 'KX13 EZJ, T837 RFL, T838 RFL']
SQL:

assistant: SELECT "Registrations" FROM "Table" WHERE "Type" = 'Retained' AND "Station Number" = 'C03';