Yes you can.
You don't have to download both Anaconda.
Only you need to download one of the version of Anaconda and need activate other version of Anaconda python.
If you have Python 3, you can set up a Python 2 kernel like this;
python2 -m pip install ipykernel
python2 -m ipykernel install --user
If you have Python 2,
python3 -m pip install ipykernel
python3 -m ipykernel install --user
Then you will be able to see both version of Python!
If you are using Anaconda Spyder then you should swap version here:
If you are using Jupiter then check here:
Note: If your Jupiter or Anaconda already open after installation you need to restart again. Then you will be able to see.