Romans 10:9 That if you confess with your mouth Jesus as Lord and believe in your heart that God has raised Him from the dead, you will be saved; (13) For "whoever calls upon the name of the Lord shall be saved."
The subject of Romans 10 is on God causing the Lord Jesus to die and resurrect for us. It is God Himself who has caused Christ to die for us. It is also God Himself who caused Him to resurrect for us. Hence, everyone who calls on the name of the Lord today is saved.
I do not know if you realize that it is a most wonderful thing to be saved just by calling on the name of the Lord. In the original language, the word call means that we only need to say His name. Today in order to contact a brother, all I have to do is to go to his door and knock twice with the door handle. This is to call upon him. I do not have to beg him to listen. I do not have to implore him. I only need to go to him and inform him with a word. This is the meaning of calling.
Since God has caused the Lord Jesus to die and resurrect for us, all who desire to be saved need only to go to God and tell Him. They will then be saved. As long as you would go to the Lord Jesus and call His name once, you will be saved. You do not need to do anything else because He has already completed all the work. That is why we say we are justified by faith and not by works (Gal. 2:16).