user: ### NOW ANSWER:
Question: I want to know the highest heat rank for overall rank of T63 and time less than 25.47
Columns: ['Heat Rank', 'Lane', 'Swimmer', 'Country', 'Time', 'Overall Rank']
Types: ['real', 'real', 'text', 'text', 'real', 'text']
Sample row: [1.0, 2.0, 'Gordon Touw Ngie Tjouw', 'Suriname', 24.9, '49']
SQL:

assistant: SELECT MAX("Heat Rank") FROM "Table" WHERE "Overall Rank" = 'T63' AND "Time" < 25.47;