user: Question: Name the total number of roll for st joseph's school when decile is less than 5
Columns: ['Name', 'Years', 'Gender', 'Area', 'Authority', 'Decile', 'Roll']
Types: ['text', 'text', 'text', 'text', 'text', 'real', 'real']
Sample row: ['Argyll East School', '1–8', 'Coed', 'Otane', 'State', 4.0, 51.0]
SQL:

assistant: SELECT SUM("Roll") FROM "Table" WHERE "Name" = 'st joseph''s school' AND "Decile" < 5.0;