Yes you can, but you will need to enable flexible-vlan-tagging and use a native vlan (documentation).
Your confif would look like:
ge-0/0/0 {flexible-vlan-tagging;native-vlan-id 20;
unit 0 {vlan-id 20;
family inet {
address 192.168.2.100/24;
}
}
unit 1 {
vlan-id 10;
family inet {
address 192.168.1.100/24;
}
}
}