user: Question: What' the series number of the episode with season number 13?
Columns: ['No. in series', 'No. in season', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: [81.0, 1.0, '"We\'ll Follow the Sun"', 'Gerry Cohen', 'Ron Leavitt & Michael G. Moye', 'September 23, 1990', '5.01']
SQL:

assistant: SELECT "No. in series" FROM "Table" WHERE "No. in season" = 13.0;