I got 20034 OBC rank in UPSEE 2019. Can i get into Gov or aided college ? Or which college i can expect ?

Based on your obc rank it is very difficult to get a good government college.  As you have not mentioned your general rank so I cannot tell completely that which Colleges you can get. You can get private Colleges. The Private Colleges where you can get admission are:
1. Inderprastha Engineering College Ghaziabad
2. Krishna Engineering College Ghaziabad
3. IIMT Engineering College Greater Noida
4. ITS Engineering College Greater Noida
5. Sharda University Greater Noida
6. Amity University Noida
These are the private Colleges where you can get admission. So go through these Colleges. You should come to know about the College by visiting their respective websites. You can also predict your college according to your rank. It also depends on the cutoff list. The cutoff list depends on the number of students appeared in the exam and the level of paper whether it is easy, moderate or difficult.