user: Question: When Massachusetts 6th is the district what is the reason for vacancy?
Columns: ['District', 'Vacator', 'Reason for Vacancy', 'Successor', 'Date of successors taking office']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Pennsylvania 15th', 'Edwin J. Jordan (R)', 'Resigned March 4, 1895', 'James H. Codding (R)', 'November 5, 1895']
SQL:

assistant: SELECT "Reason for Vacancy" FROM "Table" WHERE "District" = 'Massachusetts 6th';