user: ### NOW ANSWER:
Question: What is the smallest period (days) to have a planetary mass of 1, a stellar mass greater than 0.21 and of the type M0?
Columns: ['Stellar mass ( M☉ )', 'Planetary mass ( M⊕ )', 'Lum. (L 0 )', 'Type', 'RHAB ( AU )', 'RV (cm/s)', 'Period (days)']
Types: ['real', 'real', 'text', 'text', 'real', 'real', 'real']
Sample row: [0.1, 1.0, '8 × 10−', 'M8', 0.028, 168.0, 6.0]
SQL:

assistant: SELECT MIN("Period (days)") FROM "Table" WHERE "Planetary mass ( M⊕ )" = 1.0 AND "Stellar mass ( M☉ )" > 0.21 AND "Type" = 'M0';