user: Question: What is the largest 6-car-sets for fiscal year 1968?
Columns: ['Fiscal year', '2-car sets', '4-car sets', '6-car sets', '8-car sets', 'Total vehicles']
Types: ['real', 'real', 'real', 'real', 'real', 'real']
Sample row: [1963.0, 0.0, 15.0, 0.0, 0.0, 60.0]
SQL:

assistant: SELECT MAX("6-car sets") FROM "Table" WHERE "Fiscal year" = 1968.0;