I found this bug by just SELECTing from an existing sqlite database and getting a NotFoundException.
In the function Poco::Data::Sqlite::Utility::getColumnType, there's a call to sqlite3_column_decltype.
sqlite3_column_decltype can return "LONGVARCHAR" for string fields that can contain more than 32K letters.
The fix is to add:
_types.insert(TypeMap::value_type("LONGVARCHAR", MetaColumn::FDT_STRING));
To the Utility constructor where all the types are added.