user: Question: Which Formula has a Prefix of alkyl-?
Columns: ['Chemical class', 'Group', 'Formula', 'Prefix', 'Suffix', 'Example']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Alkane', 'Alkyl', 'R(CH 2 ) n H', 'alkyl-', '-ane', 'Ethane']
SQL:

assistant: SELECT "Formula" FROM "Table" WHERE "Prefix" = 'alkyl-';