merge two csv files by column header

i have two csv files

success.csv

"ID","Legacy ID","Field1", "Field2"

1,1111,google,news

2,2222,yahoo,news

error.csv

"Legacy ID","Field1","Field2","Message"

3333,aol,news,"Failed to upload data"

4444,cbs,news,"Alredy exists"

I want to merge these two files and create a new file with following fields. I can not use indexes as the size and order of fields will keep changing

results.csv

"ID","Legacy ID","Message"

1,1111,""

2,2222,""

"",3333,"Failed to upload data"

"",4444,"Alredy exists"

Please help I am new to linux commands