user: ### NOW ANSWER:
Question: What is the smallest diameter for Eirene Tholus?
Columns: ['Name', 'Latitude', 'Longitude', 'Diameter (km)', 'Year named']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Akka Tholus', '75.1 N', '233.0 E', 19.4, '2009']
SQL:

assistant: SELECT MIN("Diameter (km)") FROM "Table" WHERE "Name" = 'Eirene Tholus';