user: Question: What is the time for PDT when CDT is 6:38 a.m.?
Columns: ['Event', 'PDT (-7 UTC)', 'MDT (-6 UTC)', 'CDT (-5 UTC)', 'EDT (-4 UTC)']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Start penumbral (P1)', '1:55 a.m.', '2:55 a.m.', '3:55 a.m.', '4:55 a.m.']
SQL:

assistant: SELECT "PDT (-7 UTC)" FROM "Table" WHERE "CDT (-5 UTC)" = '6:38 a.m.';