user: Question: What is the lowest geohash length when the lat bits are less than 7, and the km error of ±2500?
Columns: ['geohash length', 'lat bits', 'lng bits', 'lat error', 'lng error', 'km error']
Types: ['real', 'real', 'real', 'text', 'text', 'text']
Sample row: [1.0, 2.0, 3.0, '±23', '±23', '±2500']
SQL:

assistant: SELECT MIN("geohash length") FROM "Table" WHERE "lat bits" < 7.0 AND "km error" = '±2500';