user: Question: What is the lowest density of Serravalle Scrivia?
Columns: ['Rank', 'City', 'Population', 'Area (km 2 )', 'Density (inhabitants/km 2 )', 'Altitude (mslm)']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['1st', 'Alessandria', 94191.0, 203.97, 461.8, 95.0]
SQL:

assistant: SELECT MIN("Density (inhabitants/km 2 )") FROM "Table" WHERE "City" = 'Serravalle Scrivia';