Albo robisz to w języku, osadzasz sqlite, albo używasz tego kodu SQLite, który usuwa wszystkie liczby:
UPDATE table SET column = replace(column, '0', '' );
UPDATE table SET column = replace(column, '1', '' );
UPDATE table SET column = replace(column, '2', '' );
UPDATE table SET column = replace(column, '3', '' );
UPDATE table SET column = replace(column, '4', '' );
UPDATE table SET column = replace(column, '5', '' );
UPDATE table SET column = replace(column, '6', '' );
UPDATE table SET column = replace(column, '7', '' );
UPDATE table SET column = replace(column, '8', '' );
UPDATE table SET column = replace(column, '9', '' );