What is the difference between CLOB and NCLOB?

Can you state any difference between the CLOB and NCLOB?

Answer

A CLOB stores character data encoded in the database character set. A NCLOB stores character data encoded in the national character set

SELECT parameter, value
  FROM v$nls_parameters
 WHERE parameter LIKE '%CHARACTERSET'

will show you the database and national character sets of your database.