Preferred way of adding generated column and unique partial index in schema

ALTER TABLE TaskUsers
ADD COLUMN is_assignee BOOLEAN GENERATED ALWAYS AS (role = 'assignee') STORED;

CREATE UNIQUE INDEX idx_unique_assignee
ON TaskUsers (taskId, is_assignee)
WHERE is_assignee;

ALTER TABLE TaskUsers
ADD COLUMN is_assignee BOOLEAN GENERATED ALWAYS AS (role = 'assignee') STORED;

CREATE UNIQUE INDEX idx_unique_assignee
ON TaskUsers (taskId, is_assignee)
WHERE is_assignee;