The situation shown in the figure appears

Solution:

Step 1:

Delete all files in the migrations directory in the figure

Step 2:

Delete this package and reinstall it!!

PM> add-migration Intial_one
Build started...
Build failed.
PM> add-migration Intial_one
Build started...
Build failed.
PM> add-migration Intial_one
Build started...
Build failed.
PM> add-migration IntialCreate
Build started...
Build failed.
PM> 
PM> 
PM> 
PM> 
PM> add-migration IntialCreate
Build started...
Build succeeded.
Microsoft.EntityFrameworkCore.Infrastructure[10403]
      Entity Framework Core 6.0.2 initialized 'POKEMMONContext' using provider 'Microsoft.EntityFrameworkCore.SqlServer:6.0.2' with options: None
To undo this action, use Remove-Migration.
PM> add-

OK