user: Question: What was the number of season number entries that had US Viewers of 12.30 million?
Columns: ['Season no.', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code', 'U.S. Viewers (millions)']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '" One "', 'Jean de Segonzac', 'Teleplay by: Rene Balcer Story by: Dick Wolf', 'September30,2001', 'E2101', '12.80']
SQL:

assistant: SELECT COUNT("Season no.") FROM "Table" WHERE "U.S. Viewers (millions)" = '12.30';