SQL & PL/SQL

Task;
Firstly records were required where a set of characters appeared in a string.
Problem;
The string was of datatype LONG and therefore could not appear in a WHERE clause.

Conversion to CLOB;
Problem overcome by converting type LONG to CLOB and then select where on that column.

The data within CLOB has now changed and I need to alter the LONG type column as changing from LONG to CLOB is a huge problem and basically not feaseable.

Therefore my question;

How on earth do you convert type CLOB back to LONG in order for updates to be made within the DB?

Any help is much appreciated.

Thank you in advance
Steven Tarry