Different Result with ROUND Function in MySQL

I have a table containing column of type DOUBLE, it has value 2.5 in it. When I provide this as an argument to round function i.e. round(columnName), the result is 2.
However, when I pass 2.5 hardcoded to the round function, the result is 3.
Why is the round function not showing correct data when column name is supplied as an argument? Attached are the screenshots of the problem.Different Result with ROUND Function in MySQL