Is my syntax correct for create and insert

You can also use below

INSERT INTO Persons
select  1, 'Maria' , 'Di'

Although giving columns names is good practice.

INSERT INTO Persons(PersonID , LastName, FirstName )
select  1, 'Maria' , 'Di' 


If you are calling this query from front end then do wrap it within a stored procedure other wise it will open to SQL Injections.

If you think your code may have some errors..??

then.

1> Run the code first
2> Get the Eroor
3> try to understand the Error yourself
4> try to find the solution for the error which you are getting
5>if not figureout then try to find it in google
6>Lastly ask here or any other website to find the solution.

INSERT INTO Persons(PersonID , LastName, FirstName )VALUES( 1, 'Maria' , 'Di' );

when we insert or update string/Character value to db ,value can be given within single quotes

Regards
Ramesh