Oracle Data Pump Export
It is enough to specify the schemas parameter.

expdp \'/ as sysdba\' schemas=siddhu


If you want to export only the tables, you can also add include=table:

expdp \'/ as sysdba\' schemas=siddhu include=table


The above exports the tables with indexes and triggers, but it skips procedures, sequences and other objects not directly related to tables.