user: Question: What is the US 100 rank of Champlin's Chicago 19 album with a US AC of 1?
Columns: ['Year', 'Title', 'US 100', 'US AC', 'Lead singer', 'Album', 'Label and cat#']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['July 1969', '" Questions 67 and 68 "', '71', '—', 'Cetera / Lamm', 'The Chicago Transit Authority', 'Columbia 44909']
SQL:

assistant: SELECT "US 100" FROM "Table" WHERE "Lead singer" = 'Champlin' AND "Album" = 'Chicago 19' AND "US AC" = '1';