DAX FORMULA

Hello rabeeh 
Here some Contents that might come in handy Check these out

OPTION-1
--------
Using SPLIT Function (Available in Power Query)

If you are working with Power Query (M language) instead of DAX, you can split the column directly using the SPLIT function:
In Power Query:

Right-click on the column -> Split Column -> By Delimiter -> Choose : as the delimiter.
This will create two separate columns.

And then apply condition to compair the max value and return the respective winner

OPTION-2
--------
Create a calculated column with DAX
#STATUS =
VAR _val = 'TABLEX'[SCORE]
VAR _base = FIND(":", _val, 1, LEN(_val))
VAR _left = VALUE(LEFT(_val, _base - 1))
VAR _right = VALUE(MID(_val, _base + 1, LEN(_val) - _base))

RETURN
SWITCH(
TRUE(),
_left = _right, "DRAW",
_left > _right, "Left Winner " & _left,
_left < _right, "Right Winner " & _right,
BLANK()
)

Please Provide some demo data inorder to get your required results

Thanks & Regards...