user: Question: How many members have Professor Edward Acton as vice-chancellor?
Columns: ['Institution', 'Location', 'Established', 'Gained university status', 'Vice-chancellor', 'Total Number of Students', 'Research Funding (£,000)']
Types: ['text', 'text', 'real', 'real', 'text', 'real', 'real']
Sample row: ['Birkbeck, University of London', 'London', 1823.0, 1920.0, 'Professor David Latchman', 19020.0, 9985.0]
SQL:

assistant: SELECT SUM("Total Number of Students") FROM "Table" WHERE "Vice-chancellor" = 'Professor Edward Acton';