Ok bro, first of all welcome to anasci...glad you joined. Now, you have a lot of learning to do but I'm gonna get you started on the right track. Assuming your age is 21 at least and you have a few yrs of training under your belt then you could be ready for aas. I need you to post your stats and lifting history though...please do this soon.
To answer your question, yes you can keep most of the mass without doing another one for a while, but generally people don't just do 1. You DO NOT want to do a deca and dbol cycle without any test. Deca is bad about giving you the limp noodle if you know what I mean. However, test can help to prevent that from happening. For a 1 st cycle I'd suggest test and dbol.
wks 1-10 500mg test enanthate or cypionate (250mg Mon, 250mg Thur)
wks 1-5 35mg dbol every day
For PCT (post cycle therapy) take nolvadex and/or clomid. This part is just as important as the cycle itself. So for pct do like this:
2 wks after last test shot start nolv at 40mg ed for 2 wks then 20mg ed for 2 more wks.
Or you could do Clomid at 300mg day 1, 100mg ed day 2-10, 50mg ed for 3wks