HI Rushi,
Tried it didnt make any difference. It actually removes the vlan 51, so when did the "show ethernet-switching interface ge-0/0/10", vlan 51 disappears.
The "native vlan" part in this link really confuses me "http://www.juniper.net/techpubs/en_US/junos13.2/topics/task/configuration/getting-started-els.html#jd0e225"
Thanks