user: Question: How big in metric terms is the unit that has a ratio of 1/20?
Columns: ['Unit', 'Russian', 'Translation', 'Ratio', 'Cubic inches (exact)', 'Metric value', 'Imperial', 'US Customary']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['shkalik', 'шка́лик', 'measure', '1/200', '3¾', '61.5 mL', '2.16 fl. oz.', '2.08 fl. oz.']
SQL:

assistant: SELECT "Metric value" FROM "Table" WHERE "Ratio" = '1/20';