If you want to set litecoins as your primary mining coin, use the password argument "c=litecoin." Dogecoins are merge-mined automatically by all scrypt miners.

Keep in mind that mining litecoins as your primary coin, as with primary mining any single coin, will always yield lower profitability ...

I have not merge mined Doge and LTC at the same time and cannot find how to setup a L3 for mining both at same time.
Do you have to mine with a specific command added to the password line?