user: Question: Name the number of scm system for NAnt, Visual Studio
Columns: ['Name', 'Platform', 'License', 'Windows builders', 'Java builders', 'Other builders', 'SCM system', 'Notification', 'IDE Integration', 'Other Integration']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Apache Gump', 'Python', 'Apache 2.0', 'Unknown', 'Ant , Maven 1', 'Unknown', 'CVS , Subversion', 'E-mail', 'Unknown', 'Unknown']
SQL:

assistant: SELECT COUNT("SCM system") FROM "Table" WHERE "Windows builders" = 'NAnt, Visual Studio';