user: Question: Name the least interval between doses for minimum age being 1st dose at 6 weeks old for the Diphtheria-Pertussis-Tetanus Vaccine?
Columns: ['Vaccine', 'Minimum Age at 1st Dose', 'Number of Doses', 'Dose', 'Minimum Interval Between Doses', 'Route']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Bacillus Calmette-Guérin', 'Birth or anytime after birth', '1 dose', '0.05 mL', 'none', 'Intradermal']
SQL:

assistant: SELECT MIN("Minimum Interval Between Doses") FROM "Table" WHERE "Minimum Age at 1st Dose" = '6 weeks old' AND "Vaccine" = 'Diphtheria-Pertussis-Tetanus Vaccine';