user: Question: For the 17th century entry of ɐ, what is Semi-closed initial unstressed vowels?
Columns: ['Semi-closed initial unstressed vowels', '17th c.', 'American', 'Australian', 'Examples']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['a /ə/', 'ɐ', 'ə', 'ə', 'addendum, appendix, calliope, farrago']
SQL:

assistant: SELECT "Semi-closed initial unstressed vowels" FROM "Table" WHERE "17th c." = 'ɐ';