You can not.
When you use centralized exchanges, your bought bitcoin will be credited to your bitcoin addresses on exchanges. You will have to withdraw and move them to your wallet (Ledger in this case). You will lose double fee.
One bad thing is exchanges set up their fixed withdrawal fees (that will cover many fees: transaction fees, fee when their staff verify your withdrawal request, and do it for you; fee to consolidate bitcoin inputs from deposits, etc.). Exchanges don't say it publicly but you will be charged such
expensive fees.
You can check fees (taker, maker, deposit, withdrawal) with