user: Question: What's the highest lowest number of capacity that ibrox stadium has when the average is larger than 49143?
Columns: ['Team', 'Stadium', 'Capacity', 'Lowest', 'Highest', 'Average']
Types: ['text', 'text', 'real', 'real', 'real', 'real']
Sample row: ['Celtic', 'Celtic Park', 60832.0, 45000.0, 60000.0, 56676.0]
SQL:

assistant: SELECT MAX("Lowest") FROM "Table" WHERE "Stadium" = 'ibrox stadium' AND "Average" > 49143.0;