Hi Tanveer,
My name is David Black and I'm the Director of Customer Success here at SEMrush. I can't necessarily speak for Moz but I can tell you that SEMrush offers two variations of Keyword Competition/Difficulty and both are scaled.
In our keyword reports, you'll find a column labeled "Com." (it means competitive density). This is level of competition in AdWords. But, don't be confused because the metric also appears in our Organic Keyword reports. The scale is from 0 to 1. The closer the number is to 1, the higher the difficulty.
Now, if you need some way to measure Organic difficulty, you'll want to use our Keyword Difficulty tool. This is a scale from 0 to 100% with 100% being the most difficult. It's a proprietary formula but it's based on the overall visibility of the domains which rank for that keyword in the top 20 spots.
If you need any further information feel free to write or call into our support team at mail@semrush.com.
Have a great weekend!