diff --git a/app/models/good_job/discrete_execution.rb b/app/models/good_job/discrete_execution.rb
index adc54825..e27483df 100644
--- a/app/models/good_job/discrete_execution.rb
+++ b/app/models/good_job/discrete_execution.rb
@@ -14,6 +14,9 @@ class DiscreteExecution < BaseRecord
 
     alias_attribute :performed_at, :created_at
 
+    # TODO: Remove when support for Rails 6.1 is dropped
+    attribute :duration, :interval
+
     def number
       serialized_params.fetch('executions', 0) + 1
     end
diff --git a/spec/app/models/good_job/job_spec.rb b/spec/app/models/good_job/job_spec.rb
index 0067eee1..63afcabe 100644
--- a/spec/app/models/good_job/job_spec.rb
+++ b/spec/app/models/good_job/job_spec.rb
@@ -972,7 +972,7 @@ def job_params
             created_at: within(0.001).of(good_job.performed_at),
             scheduled_at: within(0.001).of(good_job.created_at),
             finished_at: within(1.second).of(Time.current),
-            duration: be_present,
+            duration: be_a(ActiveSupport::Duration),
             error: nil,
             serialized_params: good_job.serialized_params
           )
@@ -1011,7 +1011,7 @@ def job_params
               created_at: within(1.second).of(Time.current),
               scheduled_at: within(1.second).of(Time.current),
               finished_at: within(1.second).of(Time.current),
-              duration: be_present
+              duration: be_a(ActiveSupport::Duration)
             )
           end
         end
@@ -1036,7 +1036,7 @@ def job_params
             expect(good_job.discrete_executions.first).to have_attributes(
               performed_at: within(1.second).of(Time.current),
               finished_at: within(1.second).of(Time.current),
-              duration: be_present
+              duration: be_a(ActiveSupport::Duration)
             )
           end
         end