Which lowest period's element is ruthenium?
CREATE TABLE table_name_28 (period INTEGER, element VARCHAR)
SELECT MIN(period) FROM table_name_28 WHERE element = "ruthenium"
### Context: CREATE TABLE table_name_28 (period INTEGER, element VARCHAR) ### Question: Which lowest period's element is ruthenium? ### Answer: SELECT MIN(period) FROM table_name_28 WHERE element = "ruthenium"