If we have to obtain the largest or greatest number with the digits, then we start putting largest of all the given digits in the extreme left (please note that zero would not matter here as we are starting with the largest digit in the left).
Therefore, out of 9, 0, 5 and 3, we will start the number with 9.
Now, place the remaining digits in decreasing order. Doing this, we will get:
9 5 3 0
as our required number.