Checks whether it has been set and acts accordingly to avoid exceptions
Update migration to initialize all existent rows to Description=''.
Note that after some research, default values for TEXT columns were not
supported by MySQL a few years ago, however Duplicati uses SQLite
which seems to fully support this feature. If not, a workaround is to use:
ALTER TABLE "Backup" ADD COLUMN "Description" TEXT NULL;
UPDATE "Backup" SET "Description"='' WHERE "Description" IS NULL;
ALTER TABLE "Backup" ALTER COLUMN "Description" TEXT NOT NULL;