Not sure about why you would need that or what the use case behind would be if it's in a snowflake, but technically you can only "map same column from both table" - i.e. mapping the two physical columns into one logical column - if you have them coming from two different logical table sources.
You will never ever be able to do it if you just have one LTS with joined tables. It' simply not how the metadata modelling works.
"I want to display data from AL_FACT_ENG_EBOM and AL_FACT_ENG_EBOM_LEVEL_ZERO same column is available in both the tables.."
Do you mean IF available ... what happens if it is in BOTH tables for the same dimensional intersection? Are the tables at the same grain?
You have a lot of modelling considerations to work out ...
Use drives your design - what is the use case? In business terms ...